#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
int main()
{
	int n = 0;
	int i = 0;
	int j = 1;
	scanf("%d",&n);
	for (i = 1;i <= n;i++)
	{
		j = j * i;
	}
	printf("%d",j);
}
